Sexual Maturity in Entire Male Pigs: Environmental Effects, Relations to Skatole Level and Female Puberty

Abstract

The effects of various environmental factors on sexual maturation of entire males were studied and the relationships between sexual maturation, weight of genital organs, production traits and backfat androstenone and skatole levels were investigated. The material comprised 550 crossbred entire male and 550 female pigs. All were fed a restricted dry or wet (whey or water) diet containing 0.85, 0.95 or 1.05% lysine. Entire males and females were raised in either single-sex or mixed groups. Feed was withheld in half of the pens for approximately 26 h before slaughter. The pigs were slaughtered at a live weight of 107 kg. Most of the entire males were classified as mature or well developed. Environmental factors did not affect sperm maturation. Epididymal weights for males raised together with females were heavier than for those raised in single-sex groups. Weights of genital organs were negatively (but weakly) correlated to the proportion of lean meat in the carcass. Withholding feed before slaughter resulted in higher androstenone concentrations in backfat than in animals given feed. There were positive correlations between skatole level and weight of genital organs. Lean meat percentage was negatively correlated with skatole levels.